Phrenic motor neuron degeneration compromises phrenic axonal circuitry and diaphragm activity in a unilateral cervical contusion model of spinal cord injury

► We characterize 2 new paradigms of unilateral cervical contusion spinal cord injury. ► Both paradigms produce degeneration of respiratory phrenic motor neurons and nerve. ► Both paradigms result in pathology of diaphragm muscle and neuromuscular junctions. ► Diaphragm function is chronically impaired in both injury paradigms. ► We describe important tools for understanding SCI and for evaluating therapies.